Introduction to Neuroscience – Lecture Review

These flashcards cover key definitions, structures, functions, and concepts presented in the lecture on Introduction to Neuroscience, spanning cellular neuroscience, neurophysiology, neurotransmitters, neuroplasticity, neuroanatomy, and regional nervous system organization.

What is the definition of neuroscience?

A multidisciplinary science concerned with the study of the structure and function of the nervous system.

Name at least four common branches of neuroscience.

Examples include Neuroanatomy, Neuropharmacology, Neuropsychology, Neurophysiology, Behavioral neuroscience, Developmental neuroscience, Cognitive neuroscience, Molecular neuroscience, Computational neuroscience, Neurology, Neurophilosophy.

What does neuroanatomy study?

The relationship between structure and function in the nervous system at both macroscopic and microscopic levels.

What is neurophysiology?

The subspecialty that focuses on the physiology and functioning of the nervous system, often using electrophysiological or molecular tools.

List the five primary functions of the nervous system.

Maintaining homeostasis, receiving sensory input, integrating information, controlling muscles and glands, establishing and maintaining mental activity.

Give three features that distinguish neurons from most other somatic cells.

Rich diversity in morphology, ability to generate bioelectrical signals, and specializations for intercellular communication.

Which organelle packages neurotransmitters in neurons?

The Golgi apparatus.

What neuronal organelle converts nutrients into ATP?

Mitochondria.

Name the three main parts of a neuron.

Cell body (soma), dendrites, and axon.

What is the role of dendritic spines?

They are sites where dendrites receive excitatory signals from axon terminals of other neurons.

Define Nodes of Ranvier.

Gaps between adjacent myelin segments on an axon where the axolemma is exposed.

What are Nissl bodies and their function?

Rough endoplasmic reticulum in neurons; primary site of protein synthesis to replace proteins broken down during cellular activity.

Where is the axon hillock located and what is special about it?

A cone-shaped area where the axon arises from the soma; it lacks Nissl bodies and is the site where action potentials are often initiated.

Differentiate anterograde and retrograde axonal transport.

Anterograde moves materials from soma to axon terminals; retrograde moves materials from synapse back to soma.

What are the three functional classifications of neurons?

Sensory (afferent), motor (efferent), and interneurons.

Name the three structural classifications of neurons.

Multipolar, bipolar, and unipolar (pseudounipolar).

Define neuroglia and list the four major CNS types.

Supporting cells of the CNS; types are astrocytes, oligodendrocytes, ependymal cells, and microglia.

State one key function of astrocytes.

They form part of the blood–brain barrier and help maintain ionic balance of extracellular fluid.

What is the primary job of oligodendrocytes?

Forming myelin sheaths around multiple axons in the CNS.

Which glial cell lines the brain’s ventricles and secretes CSF?

Ependymal cells.

What is the role of microglia?

They act as phagocytic immune cells within the CNS.

Which PNS glial cell forms myelin?

Schwann cells.

What structures create the blood–brain barrier?

Tight junctions between capillary endothelial cells surrounded by astrocytic end-feet (glia limitans).

Differentiate gray matter and white matter.

Gray matter contains neuron cell bodies and dendrites with little myelin; white matter consists of myelinated axon bundles.

What is the typical resting membrane potential (RMP) of a neuron?

Approximately –70 millivolts.

List three factors that establish the RMP.

High intracellular K⁺, high extracellular Na⁺, and greater membrane permeability to K⁺ than to Na⁺.

What does the Na⁺–K⁺ pump move and in what ratio?

Pumps 3 Na⁺ out and 2 K⁺ in using ATP.

Define depolarization.

A phase in which the inside of the neuron becomes less negative (more positive) due to Na⁺ influx.

What happens during repolarization?

K⁺ rapidly diffuses out of the cell, restoring the negative internal charge.

Explain the all-or-none principle for action potentials.

Once threshold is reached, an action potential fires at full magnitude; if threshold is not reached, no action potential occurs.

Differentiate absolute and relative refractory periods.

Absolute: no second AP possible; Relative: a stronger-than-threshold stimulus can elicit another AP.

How does axon diameter affect conduction velocity?

Larger diameter axons conduct action potentials faster.

Contrast continuous and saltatory conduction.

Continuous occurs along unmyelinated axons; saltatory jumps from node to node along myelinated axons, speeding conduction.

Name the three structural parts of a chemical synapse.

Presynaptic terminal, synaptic cleft, and postsynaptic membrane.

What is an EPSP?

An excitatory postsynaptic potential—local depolarization that can trigger an action potential.

List two key differences between chemical and electrical synapses.

Chemical synapses use neurotransmitters and are unidirectional with synaptic delay; electrical synapses use gap junctions, are bidirectional, and have little delay.

Define neurotransmitter.

A chemical released by a presynaptic neuron that crosses the synaptic cleft to excite or inhibit a postsynaptic cell.

Give two examples of excitatory neurotransmitters.

Acetylcholine and glutamate (others: epinephrine, norepinephrine mainly excitatory).

Name two inhibitory neurotransmitters.

GABA and glycine (others: serotonin).

Differentiate small-molecule transmitters from neuropeptides.

Small-molecule transmitters act rapidly and are synthesized in presynaptic cytosol; neuropeptides act slowly, are synthesized in the soma as part of large proteins.

Which neurotransmitter is the major conveyor of information in the PNS?

Acetylcholine.

What effect does norepinephrine have on the CNS?

Increases wakefulness and attention; overactivity can cause fear or panic.

Which neurotransmitter is associated with pleasure and reward pathways?

Dopamine.

Low levels of which neurotransmitter are linked to depression and anxiety?

Serotonin.

Which neurotransmitter is the primary excitatory transmitter in the CNS and important for learning?

Glutamate.

What is the main inhibitory neurotransmitter in the brain?

GABA (gamma-aminobutyric acid).

Name a gaseous neurotransmitter that can be excitatory and involved in long-term memory.

Nitric oxide.

Give an example of a neuropeptide involved in pain transmission.

Substance P.

Define neuroplasticity.

The ability of neurons to change their function, chemistry, or structure in response to experience or injury.

What is habituation in neuroplasticity?

Decreased response to a repeated, benign stimulus; a form of nonassociative learning.

Describe experience-dependent plasticity.

Long-lasting synaptic strengthening that requires new protein synthesis and underlies learning and memory.

What happens to neurons after axonal injury?

Axons may degenerate but can regenerate; the CNS reorganizes synapses and alters neurotransmitter release to promote recovery.

What is neurogenesis?

The creation of new neurons from stem cells in the adult brain.

Identify the two main divisions of the nervous system.

Central nervous system (brain and spinal cord) and peripheral nervous system (cranial and spinal nerves).

Name the three meningeal layers from superficial to deep.

Dura mater, arachnoid mater, pia mater.

What are the two divisions of the autonomic nervous system?

Sympathetic (fight-or-flight) and parasympathetic (rest-and-digest).

List the four types of nerve fibers based on origin and destination.

Somatic afferent, somatic efferent, visceral afferent, visceral efferent.

From which germ layer does the CNS develop?

Ectoderm.

Name the three primary brain vesicles formed during development.

Prosencephalon (forebrain), mesencephalon (midbrain), rhombencephalon (hindbrain).

What structures derive from the telencephalon?

The cerebral hemispheres (cerebrum) and lateral ventricles.

List the three parts of the brainstem.

Medulla oblongata, pons, and midbrain.

State two vital reflex centers located in the medulla oblongata.

Centers regulating heart rate and respiration (also swallowing, vomiting, etc.).

What sleep-related function is associated with the pons?

Initiation of rapid eye-movement (REM) sleep.

Which brainstem region serves as a visual reflex center?

The midbrain.

What is the role of the reticular formation?

Regulates consciousness and the sleep–wake cycle, and coordinates rhythmic activities such as breathing.

Which cranial nerves are purely sensory?

CN I (Olfactory), II (Optic), VIII (Vestibulocochlear).

Name three functions of the cerebellum.

Coordinating muscle movements, maintaining posture, and maintaining balance.

What are the three anatomical parts of the cerebellum?

Flocculonodular lobe, vermis, and two lateral hemispheres.

List the four components of the diencephalon.

Thalamus, subthalamus, epithalamus, hypothalamus.

Which diencephalic structure is the relay station for all sensory impulses except smell?

Thalamus.

Give four functions regulated by the hypothalamus.

Circadian rhythm, appetite, thermoregulation, emotional behavior (also endocrine control and sexual drive).

Match each cerebral lobe with one key function: frontal, parietal, temporal, occipital.

Frontal – motor control and motivation; Parietal – somatic sensation; Temporal – hearing and memory; Occipital – vision.

To what vertebral level does the adult spinal cord typically extend?

Lower border of L1 (about the upper border of L3 in children).

What is the conus medullaris?

The tapered inferior end of the spinal cord at approximately L1–L2.

Define cauda equina.

Bundle of spinal nerve roots that descend below the conus medullaris, resembling a horse’s tail.

Which spinal root is sensory, and what ganglion does it contain?

The dorsal (posterior) root; it contains the dorsal root (spinal) ganglion.

What produces cerebrospinal fluid (CSF)?

The choroid plexus.

How is CSF returned to the venous system?

Through arachnoid villi into the bloodstream.

What is the function of sensory (afferent) neurons?

Neurons that transmit impulses from sensory receptors in the peripheral nervous system (PNS) to the central nervous system (CNS).

What is the role of motor (efferent) neurons?

Neurons that transmit impulses from the central nervous system (CNS) to muscles and glands (effectors) in the peripheral nervous system (PNS).

What are interneurons and where are they found?

Neurons located entirely within the central nervous system (CNS) that connect sensory and motor neurons and integrate information.